Rennet is an essential ingredient that is mostly in the cheesemaking process to coagulate and separate into curds and whey by using milk.
But if your rennet has been sitting around for a while, how can you tell if it has expired?
As a liquid enzyme solution, rennet does have a limited shelf life.
So yes. Rennet can go bad.
In this post, I’ll breakdown when Rennet goes bad including the shelf life of liquid and tablet rennet. Plus, you’ll learn how to test its freshness and the signs of bad Rennet.
I’ll also talk about the impacts of using expired rennet in your cheesemaking process.
Shelf Life of Rennet
Liquid rennet can last 7-8 months when refrigerated properly.
Rennet tablets can have a shelf life of around 2 years at room temperature, or 5 years if stored in the freezer.
Always check the best-by date on your specific rennet package as a guide.
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But if you’re unsure of how old it is, you can test the freshness of it.
Signs of Bad Rennet
How do you know whether your rennet has truly gone off?
Here are a few indicators that your rennet should be beyond the expiry date:
- Produces only soft curds or whey separation
- Fails the at-home freshness test, which was in detail above
- Smells unpleasant or “off”
- Colour is different or grown mold
- Been in the storage improperly at high temps over a long period
Using expired products can lead to suboptimal cheese texture and yield.
So if you are not sure and in doubt, test your rennet or buy a certified fresh supply.
How To Test If Rennet Has Gone Bad
It only takes a few simple ingredients to check if your rennet is still active or if it has lost potency and gone bad.
First of all, you’ll need the following:
- 1 cup of milk
- 1⁄4 of rennet tablet or 1⁄4 of tsp liquid rennet
- 2 tbsp of non-chlorinated water
Here’s the testing process:
Step 1: Heat your milk up to 90°F.
Step 2: Dissolve the rennet in the water and stir.
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Step 3: Add the rennet solution to your warm milk base and gently stir it for about 30 seconds.
Step 4: Observe it for over 6 minutes. After the time gap, the milk should begin to firm up and form a curd that can hold a clean knife cut.
If your tested rennet does not clot the milk in this way, then it is no longer good to use.
Which means it’s time to purchase a new product.
Can An Expired Rennet Make You Sick?
No. Consuming small amounts of expired rennet is not generally considered a health risk. This is especially true when it’s properly aged and cooked into complex cheeses over time.
The rennet will not have retained much enzymatic activity that could pose issues.
However, individuals who may be highly sensitive to enzymatic food should still avoid consuming cheeses that are made with bad rennet.
And it’s best to also not directly ingest old liquid rennet in concentrated forms.
Storing Rennet For Maximum Freshness
To get the most shelf life out of your rennet, be sure to store it properly this way:
Liquid Rennet Storage
Liquid rennet must be refrigerated at all times until you use it again.
Keep it tightly sealed and avoid temperature fluctuations.
Rennet Tablet Storage
Tablets should be kept frozen.
If freezing is not possible, a cool, dark place like a cupboard works as well. Just avoid humidity or rapid temperature changes.
Once rennet containers are opened, try to use them up within a reasonable timeframe and watch closely for any changes in the smell, texture, or taste until your next cheese batch.
FAQs
Can Rennet Be Harmful To Humans?
Your recipe didn’t turn out quite right because you think the rennet was off?
No worries, the cheese itself won’t be harmful after aging. But you may be disappointed with odd flavors or textures.
When making something you plan to consume, always start your cheesemaking journey with a fresh and potent rennet that you can trust for the best, safest results.